The girl at the table opposite me is doing something very strange with her sandwich. She has cut it into exact quarters and is slowly, gingerly dissecting each one as if it were a bomb about to go off, removing the bread, wiping off the mayonnaise with a paper towel, piling the meat and lettuce into precise piles with a tiny scrape of mustard and eating them hurriedly, her hands trembling. You might expect the other people in the cafe to notice, but this is New York, where the spectacle of hungry, pool-eyed young women ritually starving themselves has become routine. It's Eating Disorder Awareness Week, but awareness doesn't seem to be the problem here.

I watch the girl in the glass of the cafe window. I have nothing in common with her except that we happen to be the same person. Or rather, we were: it's eight years this week since I was admitted to hospital with anorexia, and three years since I made a full recovery, but now and then around this time of year, the old, weird habits creep back; food the enemy, every mirror a traitor. I don't know quite what happened to the skinny, miserable seventeen year old I used to be. Over the long months of learning that it was alright to take up space, I suspect I may have eaten her. But I see people just like her every day on the streets of every major city, ghost-people with mad eyes staring blankly ahead, spindly limbs pistoning with manic energy, wrapped up against a chill that can't be fought, and they are women of all ages, and at least 15 per cent of them are men.

Eating disorders, however, are still seen as diseases peculiar to pretty young white women, which perhaps explains why years of "awareness raising" have led to a great deal of glamour and mystery surrounding this deadliest of mental illnesses and precious little understanding. After thousands of histrionic articles conveniently illustrated with pictures of half-naked models looking upset, the number of people with eating disorders is still rising, and we are no closer to solving one of the great mysteries of modern life - namely, why so many of our brightest and best young people are starving themselves slowly to death.

The best answer we seem to have come up with is "magazines". This says rather more about what society thinks goes on in the minds of teenage girls than it does about the cause of an epidemic that kills thousands of young people every year, and leaves countless more living half-existences with the best dreams of their single lives shrunk to the size of a dinner plate.

The most important thing to understand about eating disorders is that starving, binging, purging and puking are not causes of distress. They are symptoms of it. The diseases are replete with contradictions, at once about denying hunger for food, for rest, for fun, for sex, for freedom whilst the sufferer starves for it all to the point of death. Most curiously, the pathologies involve an itricate interplay of aggression and compliance. Eating disorders are what happens when youthful rebellion cannibalises itself.

In Italy, there is a tradition called "sciopero bianco" - the white strike. Here, it is known as work-to-rule. Workers who are not permitted to strike fight their bosses by doing only what is required of them - to the letter. Nurses refuse to answer phones that ring at 17:01. Transport workers make safety checks so rigid that trains run hours behind schedule. Eating disorders, particularly anorexia, are to riots in the streets what a white strike is to a factory occupation: women, precarious workers, young people and others for whom the lassitudes of modern life routinely produce acute distress and for whom the stakes of social non-conformity are high, lash out by doing only what is required of them, to the point of extremity. Work hard; eat less; consume frantically; be thin and perfect and good; conform and comply; push yourself to the point of collapse. It is no accident that eating disorders are often associated with obsessive overwork and perfectionism at school, in the workplace or in the home. We followed all the rules, sufferers seem to be saying - now look what you made us do.

Raising awareness is important, but awareness without understanding is just a way to boost newspaper sales and make starvation acceptable as a silent rhetoric of female distress. Fighting eating disorders, really fighting them, takes stamina, and courage, and the determination to live fully, whatever the cost.